Mineral, Part Of A Rock

Rugose Coral Fossil

Order Rugosa (Tetracorallia)

Gold Nugget

Native Gold (Au)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Tektite (Indochinite)

Tektite (High-silica natural glass, primarily SiO2 with Al2O3)

Quartz with Mica (Schist/Pegmatite fragment)

Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)

Hypersthene (or Enstatite/Ferrosilite)

Orthopyroxene series (Mg,Fe)SiO3 - specifically, historically hypersthene (intermediate member) now referred to as Enstatite (Mg-rich) or Ferrosilite (Fe-rich)

Amethyst

Quartz (Silicon Dioxide with iron impurities), SiO2

Lepidolite (likely)

K(Li,Al)3(Al,Si)4O10(F,OH)2 (Phyllosilicate mineral, part of the mica group)

Fossil brachiopod shell

Likely spiriferid or strophomenid brachiopod; calcium carbonate (primarily calcite)

Quartz Pebble

Silicon Dioxide (SiO2)

Chalk (Sedimentary Pebble)

Calcium Carbonate (CaCO3) - Biogenic Limestone

Rounded limestone pebble

Limestone, predominantly calcite (CaCO₃)

Pink Granite (Water-worn Cobble)

Granite (Alkali-feldspar granite)

Granite Pebble

Felsic Plutonic Rock (primarily Quartz, Feldspar, and Mica)

Petrified Wood

Silicified Wood (SiO2)

Botryoidal Chalcedony (Desert Rose / Agate)

Silicon Dioxide (SiO₂)

Amber

Succinite (Fossilized Resin)

Fossiliferous Chert Nodule

SiO2 (Microcrystalline Quartz) with fossil inclusions

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Quartz (Druzy Quartz)

Silicon Dioxide (SiO2)

Amber

Fossilized Tree Resin (Generic formula: C10H16O)

Tiger’s eye

Quartz variety, primarily silicon dioxide (SiO₂); fibrous quartz pseudomorph after crocidolite asbestos

Amber / Copal

Fossilized Tree Resin (Succinate)

Fossilized echinoid (sea urchin), likely a flint/chalk-associated test

Echinoid fossil; likely a regular echinoid such as Echinocidaris or related taxon, composed mainly of recrystallized calcite (CaCO₃)

Weathered graywacke or sandstone cobble

Lithic/feldspathic sandstone; exact identification requires a fresh break or thin section

Quartz pebble

SiO2

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Weathered, iron-stained quartzite pebble

Quartzite; predominantly microcrystalline quartz (SiO₂) with iron-oxide staining

Milky Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Ironstone (Limonitic Sandstone)

Ferruginous Sandstone (rich in Limonite: FeO(OH)·nH2O)

Nephrite Jade

Nephrite

Slag Glass (Leland Blue variant)

Anthropogenic Vitreous Silicate

Diabase (Greenstone Pebble)

Diabase or Dolerite

Quartz Druze on Matrix

Silicon Dioxide (SiO2)

Aventurine (likely Green Aventurine)

Silicon Dioxide (SiO2) with various inclusions

Milky Quartz (or Vein Quartz)

Silicon Dioxide (SiO2)

Quartz (Milky or Iron-Stained)

Silicon Dioxide (SiO2)

Rounded river pebble, likely weathered quartzite or sandstone

Quartzite (mostly SiO₂), possibly ferruginous sandstone

Lepidodendron fossil (Scale Tree Bark)

Lepidodendron (Lycophytina class)

Seraphinite

Clinochlore (a variety of the chlorite group)

Tumbled pale green aventurine (probable)

Quartz, SiO₂, with dispersed fuchsite or other green inclusions